To do so gets you little approbation (3)
I believe the answer is:
rob
'to do' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.
'gets you little approbation' is the wordplay.
'ROB' is hidden within the letters.
However, I am uncertain how this is indicated.
'so' acts as a link.
Can you help me to learn more?
(Other definitions for rob that I've seen before include "Nick" , "sack" , "boy's name" , "Take without consent from the owner" , "Unlawfully take property from (someone)" .)